Structure and function of weevil assemblages (Coleoptera, Curculionoidea) in epigeon of oak-hornbeam forests in SW Slovakia

In 1999-2002, we studied the weevil assemblages in the epigeon of oak-hornbeam forests in SW Slovakia, with regard to assemblage structure, species richness, seasonal occurrence and ecological requirements of individual species. The investigation was performed on 10 study plots (forest stands of the age from 40 to 100 years) in the Male Karpaty Mts and Trnavska pahorkatina hills, SW Slovakia. Each site was affected, to some extent by human activities of which forest fragmentation and pollution with calcareous dust were the most important. The soil macrofauna was collected by sifting the litter, surface layer of soil and remnants of twigs. Altogether 4,090 individuals of weevils classified into 78 species, 43 genera and 4 families were recorded. The number of species found at the particular sites ranged from 22 to 31 species. The mean abundance of weevils varied from 2.09 to 49.71 ind.m-2. Geophilous species Ceutorhynchus pallidactylus, geobionts Acalles fallax, Barypeithes chevrolati, Barypeithes mollicomus, Brachysomus hirtus, Trachodes hispidus and geoxenes Ceutorhynchus obstrictus and Sitona macularius predominated in the material from the oak-hornbeam forest epigeon. The canopy architecture and content of exchange bases in the leaf litter from amongst 13 gradient and 2 categorial variables analysed had direct and significant influence on the structure of epigeic weevil assemblages. The forest fragmentation caused increase the abundance of herbicolous, euryhygric and ubiquitous species in the epigeon of island woods. The weevil community was less abundant and unstable in the forest site polluted with calcareous dust.